Oracle Key Concepts - Make Sure You Know All!
The content taken from
Title: Oracle Database Administration Concepts &
Implementation Made Simple
ISBN: 0-9770739-0-4
Author: Asim Abbasi
Oracle Key Concepts - Make Sure You Know All!
41. Non-Shared part of Oracle memory architecture is also called PGA or
Program Global Area.
42. The utilization of PGA depends how you configure the Oracle Server.
43. Oracle Server can be configured to run as Dedicated Server mode or
Shared Server mode.
44. Unlike SGA where RAM is shared by all the background process, PGA is
utilized by server process for sorting, session information and as stack
space.
45. RECO, LGWR, SMON, PMON, ARCn etc. are all background processes.
46. SGA is the shared part of memory architecture of Oracle.
47. Oracle can be configured to run as dedicated server mode or shared
server mode.
48. There would not be any Request and Response Queues in a dedicated
server configuration.
49. There would not be any dispatcher process in dedicated server mode.
50. For each connected user the there would one dedicated server
process.
51. The idle time of server will be more but this configuration has the
highest performance factor.
52. Oracle two modes of operations.
a. Shared Server
b. Dedicated Server
53. Utilizing Shared Server mode you can have least Idle Time but
performance would be as that of Dedicated Server mode.
54. If system resources are not a problem keeping in mind the connected
users, then always go with dedicated server mode.
55. Software application (e.g. MS Word) has GUI whereas a Software
Process is independent of GUI and requires no user interaction (e.g.
LGWR)
56. Depends on the way you program a Process, usually a process runs
when certain event happens and re-runs if the event happens again.
57. DBWR writes the dirty buffers from Database Buffer Cache to the data
files.
58. LGWR writes the redo log buffers from Redo Log Cache to the redo
files.
59. Log Switch happens whenever LGWR process finishes writing one Redo
Log file and moves to the next one.
60. LGWR process will start new ARCn process whenever ARCn gets
overloaded.
Oracle Key Concepts - Make Sure You Know All!
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